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HA RD WICKE'S SCIENCE- G OSSIP. 



anchor the plant firmly in a soft and oozy soil. They 

 had long cylindrical rootlets so articulated that when 

 they dropped off they left regular rounded scars. 

 Under every bed of coal is found a bed of clay filled 

 with these singular roots, shewing that the first step 

 towards the accumulation of a bed of coal was the 

 growth of a forest of Sigillarice. Indeed, in some of 

 the coarser and more impure coals we can see that 

 the mass of coal is made up of flattened Sigillarioe, 

 mixed with vegetable debris of all kinds, from the 

 undergrowth of ferns and other plants which grew 

 beneath their shade, and often vast quantities of 

 Lepidodendroid spores. These forests gradually sank 

 down in the marshy soil, some of the trees still re- 

 maining erect ; other forests grew above them, so 

 that in the course of ages as many as seven or eight 

 forests grew one above the other, and all sank at last 

 and were buried. This growth of successive forests 

 took place in the Lignite Tertiary as well as in the 

 ■Carboniferous period, and gives us 'the impression of 

 a vast lapse of time. 



Sir J. W. Dawson believes that amongst the eighty 

 species of Sigillarise, a "great range of organisation 

 must have been found, some of which will eventu- 

 ally be classed with the Lepidodendra as Lycopods, 

 while others will be found to be naked-seeded phano- 

 gams, like the pines and cycads." This statement 

 must also doubtless be received not in a Darwinian, 

 but, so to speak, in a " Pickwickian sense." 



We now come to the important group of Calamites ; 

 these are tall, cylindrical branchless stems, with 

 whorls of branchlets bearing needle-like leaves, which 

 spreading from the base form dense thickets, like 

 .southern cane-brakes. In their mode of growth and 

 fructification they resemble gigantic horse-tails, but 

 the manner by which their stems are strengthened 

 resembles that of exogenous woods. It would seem 

 from the way in which dense brakes of these Calamites 

 have been preserved, that they spread over low and 

 inundated flats, and formed fringes on the sides of 

 the great Sigillaria forests. Many beautiful plants 

 intermediate between Calamites and Rhizocarps grew 

 in these brakes, bearing whorls of graceful leaves of 

 various shapes. The Lycopods and Calamites have 

 been familiar to us from our childhood, there being 

 something in their resemblance to our familiar club- 

 mosses and horse-tails which impressed them on the 

 memory. But the strange family of Cordaites are by 

 no means so well known ; they are unlike an34hing 

 we are accustomed to, and belong to one of those 

 intermediate groups, or connecting links, which 

 remind a zoologist strongly of those generalised forms 

 of mammals of the Eocene, where the characteristics 

 of orders now distinct are inextricably combined. The 

 Cordaites "approach closely on the one hand to the 

 broader leaved yews, like the Gingko of China, and 

 on the other hand have affinities with Cycads, and 

 even with the Sigillarix." In the formation of their 

 wood they show transitions from the imperfectly 



formed stems of Sigillarice to the more highly 

 organised trunks of modern conifers, and in the young 

 twigs of the balsam-fir the ordinary Cordaite formation 

 of wood may still be seen. This consists of a " large 

 cellular pith, divided by horizontal partitions into flat 

 chambers ; this pith was surrounded by a thick ring 

 of barred or scalariform tissue, and as the stem grew 

 in size a regular ring of woody wedges was formed, 

 with disc-bearing tissue like that of pines." They 

 were beautiful trees, with their leaves in some species 

 growing in thickly-set spikes, but perhaps oftener 

 developed on each set of the branches, in a manner 

 very unlike any modern plant that I am acquainted 

 with. These many-nerved leaves had rows of stomata 

 or breathing pores, and attached by somewhat broad 

 bases to the leaves and branches ; the fruit consisted 

 of "clusters of nutlets, often provided with broad 

 lateral wings for flotation in the air, sometimes 

 covered only with a pulpy envelope." These trees 

 had great reproductive powers, producing numerous 

 seeds in long spikes or catkins. 



Many Conifers are found in the Carboniferous 

 period ; none as yet bearing cones, but all apparently 

 related to the modern yews and spruces. Some 

 slightly resembled the modern Araucarias, others had 

 broad fern-like leaves like those of the Gingko. Pro- 

 bably they were in the main "inland and upland 

 trees, mostly known to us by drifted trunks borne by 

 river inundations into the seas and estuaries." 



Last and not least, where beauty is concerned, there 

 was a wealth of exquisite ferns in these old coal- 

 forests, and noble tree-ferns such as tropical forests 

 alone possess now. Of the "eight families into 

 which modern ferns are divided, four at least go back 

 to the coal period." Their spore cases show the 

 usual series of transitional forms, from a low to a high 

 type, and those with the simplest spore cases, without 

 a jointed elastic ring, are most commonly found in 

 the Devonian and Lower Carboniferous. 



The succeeding Mesozoic age as far as the Upper 

 Cretaceous period, presents fewer points of interest 

 in its fossil botany. The Triassic and Permian for- 

 mations show a time of " great physical disturbance, 

 more especially by great volcanic eruptions discharging 

 vast beds and dykes of lava and layers of volcanic ash 

 and agglomerate. The thick beds of sediment that 

 had been accumulating in long lines along the primi- 

 tive continents had weighed down the earth's crust. 

 Hence in the Appalachian region of America we 

 have the Carboniferous beds thrown into abrupt folds, 

 their shales converted into hard slates, their sandstones 

 into quartzite, and their coals into anthracite," and 

 similar treatment befel the coal fields of Wales and 

 of Western Europe. The flora and fauna of Paleozoic 

 times gradually die out, to be replaced by other 

 species of our old friends the Calamites, by enormous 

 numbers of conifers resembling the yews and spruces, 

 and at last in the Lower Cretaceous by cone-bearing 

 pines ; whilst in the animal world the giant newts 



